Vasculitis refers to a collection of rare disorders characterized by inflammation of blood vessels. Each condition is identified by specific patterns of blood vessel and organ involvement, as well as distinct abnormalities in laboratory tests. The precise causes of vasculitis are often unclear, but abnormalities are a common trait. Some examples include Kawasaki disease, Behcet's disease, polyarteritis nodosa, granulomatosis with polyangiitis, Takayasu's arteritis, Churg-Strauss syndrome, giant cell arteritis, and Henoch-Schonlein purpura. Vasculitis can also occur alongside infections, certain chemical exposures like amphetamines, cancers such as lymphomas, and rheumatic diseases. Laboratory tests in patients with active vasculitis typically show signs of inflammation, and depending on the extent of organ involvement, various organ function tests may reveal abnormalities. A definitive diagnosis is usually made after a biopsy of affected tissue shows the specific pattern of blood vessel inflammation. Treatment varies based on the type, severity, and organ involvement, focusing on reducing inflammation and suppressing the immune system. Common treatments include medications like prednisone and immune-suppressing drugs such as cyclophosphamide (brand name: Cytoxan). Vasculitis is also known as vasculitides in its plural form.